Method for the manufacture of cord

ABSTRACT

A method for the manufacture of cord which comprises passing upwards through a rotating hollow spindle a continuous filament yarn substantially free from twist and simultaneously drawing off from the spindle a continuous filament yarn initially in a twisted condition, passing the yarn through a guide means thus causing the yarns to become doubled and form a cord in which the yarns are substantially free from twist. Instead of two separate yarns a continuous length of yarn may be used, the first portion being twisted and then doubled with the second portion of yarn of which the following is a specification.

[ 51 June 13, 1972 [54] METHOD FOR THE MANUFACTURE OF CORD [72] Inventors: Ronald S. Goy; Peter L. E. Moring, both of Sutton Coldfield, England Dunlap Holdings Limited, London, England [22] Filed: Sept. 28, 1970 [21] Appl.No.: 76,008

[73] Assignee:

[30] Foreign Application Priority Data Oct. ll, 1969 Great Britain ..50,034/69 [52] U.S.Cl ..57/157 TS,57/18,57/64 [51] Int. Cl ..D02g 3/48 [58] Field ofSearch ..57/3,7, l2, 17, 18, 35, 62,

[56] References Cited UNITED STATES PATENTS 3,425,209 2/1969 Goy ..57/157 Whitehead ..57/18 Vibber Geyer, Jr. et al.

Primary Examiner-Werner H. Schroeder Attorney-Stevens, Davis, Miller & Mosher 57 ABSTRACT A method for the manufacture of cord which comprises passing upwards through a rotating hollow spindle a continuous filament yarn substantially free from twist and simultaneously drawing off from the spindle a continuous filament yarn initially in a twisted condition, passing the yarn through a guide means thus causing the yarns to become doubled and form a cord in which the yarns are substantially free from twist. Instead of two separate yarns a continuous length of yarn may be used, the first portion being twisted and then doubled with the second portion of yarn of which the following is a specification.

14 Claims, 4 Drawing Figures METHOD FOR THE MANUFACTURE OF CORD This invention relates to a method for the manufacture of cord and particularly to a method for the manufacture of cord by doubling together continuous filament yarns, and is an improvement in or modification of the invention described in U.K. Pat. No. 1,172,358.

According to one aspect of the present invention a method for the manufacture of cord comprises passing upwards through a rotating hollow spindle a continuous filament yarn substantially free from twist and simultaneously drawing off from the spindle a continuous filament yarn initially in a twisted condition, passing the yarns through a guide means thus causing the yarns to become doubled and fonn a cord in which the yarns are substantially free from twist.

According to a further aspect of the invention a method for the manufacture of cord comprises continuously passing a continuous filament yarn substantially free from twist upwards through a rotating hollow spindle, inserting twist into a first portion of the yarn and winding the twisted yarn on to the spindle, subsequently drawing the first portion of the yarn from the spindle and through a guide means together with a second portion of yarn which is free from twist, thus causing the first portion to become doubled with the second portion of yarn to form a cord in which the two portions of yarn are substantially free from twist.

The continuous filament yarns as used in the method of the present specification is understood to include a rnonofilament or multifilament yarn or tape made by drawing slit film.

Methods used heretofore for manufacturing doubled cord have involved imposing twist in two single yarns to be doubled together, and subsequently doubling the two yarns together in such a manner that the initial twist in the single yarns is removed while at the same time the two yarns are each given a doubling twist, i.e. each is caused to adopt a spiral configuration. This process is laborious and expensive in that it involves preparing two packages of twisted yarns, assembling the two packages side-by-side on a doubling frame, doubling the two yarns together and collecting the doubled cord on a further package. Doubling is usually effected by down-twisting which involves the use of a ring-traveller, or by up twisting which could involve the use of a flyer. Disadvantages of both these methods are that the speed of the process is controlled by the maximum speed at which the ring-traveller or flyer can operate.

The present invention provides a process in which it is necessary only to twist one of the single yarns or oneportion of yarn, i.e. only half of the number of packages of twisted yarns need be produced.

The process has a further advantage that the speed thereof is not limited to the speed of a ring-traveller or a flyer. In order to obtain satisfactory doubling by the methods of the present invention it is necessary merely to obtain the correct ratio of spindle speed to yarn throughput; spindle speeds at least twice as great as those of conventional doubling apparatus can be used.

The yarn or first portion of yarn essentially in a twisted condition will usually be carried on a bobbin which may be either located on the hollow spindle or integral with the spindle.

In a preferred method of the present invention the bobbin is provided with a top flange in the shape of an inverted cone. A cone with an included angle of 90 is preferred.

The rotation of the hollow spindle is such that the twisted yarn is caused to be thrown off and unwound from the bobbin. The yarn initially in an untwisted condition is fed into the bottom of the hollow spindle and the resulting cord is drawn off at a point above the spindle also at a constant rate.

It will be appreciated that rate of feed-in of theuntwisted yarn should be greater than the rate of take-up of the cord, but the two will be a constant ratio for a given speed of feed-in. The difference in the rates is to allow the apparently shortening of the yarn due to its being caused to adopt a helical path in the doubled cord.

The control which the present invention enables to be exercised over both the feed-in and take-up rates is advantageous in that it enables a degree of control to be exercised over the twist uniformity of the doubled cord. A disadvantage of the prior processes discussed above is that either the rate of feedin of yarn is controlled and not the rate of take-up (downtwisting) or vice-versa, (up-twisting), and this tends to result in twist variability in the resulting cord. Although there is no direct control in the method of the present invention over the rate of feed-in of the twisted yarn unwinding from the bobbin, it has been found that providing the speed of rotation of the bobbin is sufficiently high, twist variability due to non-uniform feedin of this yarn do not tend to arise. Spindle speeds in excess of 5,000 r.p.m. are preferred and speeds of up to 10,500 r.p.m. can be attained.

As hereinbefore stated the yarn initially in a twisted condition becomes substantially free from twist (other than doubling twist) during the doubling operation. The yarn initially in an untwisted condition becomes twisted prior to entry into the spindle. This twist imposed on the initially untwisted yarn is removed during doubling so that in the cord both yarns are substantially untwisted but each has the same helical arrangement.

The important features to obtain a uniform cord are the spindle speed and the rate of throughput of the yarns. It is usual to fix the spindle speed and to adjust the rate of throughput of the yarns accordingly. The actual doubling step is the same as in conventional methods, i.e. it involves the doubling together of two twisted yarns in such a way that the twist in the individual yarns is removed. However, the method of the present invention has the advantage that due to the control it is possible to exercise over rate of feed-in and take-u a cord of greater twist uniformity can be produced.

As hereinbefore stated the rate of production of a doubled cord by conventional techniques is controlled by the speed of a ring-traveller or a flyer. The speed is limited due to the fact that the ring-traveller or the flyer moves in contact with a solid surface and the frictional forces developed result in build-up of heat which if it becomes excessive could result in stoppage of the machine. Spindle speeds giving traveller speeds of up to 153 ft./sec., e.g. 5,000 r.p.m. on a 7 inch diameter ring are the maximum which could be expected from conventional apparatus. As hereinafter explained, the present invention is not limited in this way and high bobbin speeds, and correspondingly high rates of production of cord are possible. For example, using a spindle speed of 10,500 r.p.m. carrying a yarn of twist 12.4 turns per inch, it is possible to draw cord off from above the spindle at a rate of 24 yards per minuted.

The present invention is applicable to the production of cords from any synthetic continuous filaments, e.g. non-thermoplastic filaments such as rayon, but it is particularly applicable to the production of cord from thermoplastic filaments since it is possible in this case to heat-set the resulting cord. Usually, both the initially twisted yarn and the initially untwisted yarn are multifilament yarns but it is to be understood that, if desired, both yarns can be a single monofilament yarns, or one yarn can be monofilament and the other multifilament. In the case where a multifilament yarn is used it is not necessary to employ yarns in which all the filaments are thermoplastic to make a cord which can be heat-set, in fact, as little as 10 percent of the filaments need be thermoplastic in order to confer heat-settability on the yarn. Examples of suitable thermoplastic filaments are nylon, poly(ethy1ene terephthalate) and polypropylene.

The present invention has the further advantage that due to the control which can be exercised over cord draw-off it enables the cord prior to wind-up to be treated by any conventional textile processing technique. For example, the cord can be dyed, coated or rubberized prior to wind-up. A particularly suitable technique is to pass the cord directly into a fluidizedbed of solid particles which can conveniently be heated at an elevated temperature, for example, 240 C. to heat-set the cord. Stretching of the cord during passage through the fluidized-bed of solid particles can advantageously be performed to produce a heat-set cord which is less susceptible to shrinkage or excessive stretching than a cord which has not been subjected to the treatment. By heat-setting or hotstretching the cord immediately after doubling, before the foldings have adopted a permanent set, any small nonuniformity, produced for instance by slight maladjustment of the machine, will be reduced.

By employing the method of one aspect of the invention it is possible using a continuous process, to form from a single length of yarn. This method has the advantage that it is not necessary to stop the machine between the twisting of the yarn and the doubling of the twisted yarn with the untwisted yarn.

In order to form a cord by this method, a first portion of yarn which is substantially free from twist is passed up a rotating hollow spindle and is then twisted by passing the portion of yarn, for example, through a traveller which is slidably mounted on a ring which is capable of moving up and down with respect to the spindle and which encircles the spindle and then winding the portion of twisted yarn round the spindle or a bobbin carried on the spindle. When the spindle or bobbin is filled with twisted yarn and the ring has reached the bottom if its traverse the traveller is disconnected from the ring and at the same time the twisted portion of yarn is drawn off the spindle or bobbin and through the guide ring, thus causing it to become doubled with a second portion of yarn which is free from twist.

The method of the present invention is particularly applicable to the production of tire cords, especially when the process involves treatment with a fluidized-bed of solid particles as described above. It is a particularly desirable feature of tire cords that there should be little tendency for the cord to untwist (i.e. it should be heat-set) and excessive potential stretching or shrinking of the cord should be avoided. The present invention enables the production of a cord which fulfills each of these requirements. Tire cords produced by the method of the invention can be used as reinforcement in tires in the usual manner.

Apparatus suitable for performing the method of the present invention will now be described by way of example only with reference to the accompanying drawings in which,

FIG. 1 is a diagrammatic representation of an apparatus for producing a bobbin of twisted yarn;

FIG. 2 is a diagrammatic representation of an alternative apparatus for producing a bobbin of twisted yarn;

FIG. 3 is a diagrammatic representation of an apparatus for doubling a twisted yarn with an untwisted yarn; and

FIG. 4 is a diagrammatic representation of a split-ring for use in forming a cord by a continuous method.

In FIG. 1 a hollow spindle 9 carrying a bobbin 10 provided with a cone-shaped flange 16 is vertically mounted on a bearing 11 and is encircled by a ring 12 on which is slidably carried a traveller 13. Below the center of the hollow spindle 9 is mounted a feed-nip roller system 14.

In operation to produce a bobbin of twisted yarn, a yarn 15 is drawn through a feed-nip roller system 14 and up through the center of the hollow spindle 9. The spindle 9 is caused to rotate and the movement of the yarn is through the traveller 13 causes the traveller 13 to circumnavigate the spindle 9 by sliding on the ring 12 and thereby inserts twist into the yarn 15.

The ring 12 is made to move up and down. The traverse motion is operated by magnetic clutches controlled by limit switches which are activated by contact with the ring 12. The lower limit switch is stationary whereas the position of the upper limit switch is changed by a suitably shaped cam which ensures that the yarn build conforms with the shape of the flange 16.

In FIG. 2 a hollow spindle 9 carrying a bobbin 10 provided with a cone-shaped flange 16 is vertically mounted on a bearing 11 and is encircled by a ring 12 on which is slidably carried a traveller 13. Above the center of the spindle is mounted a pigtail guide ring 17 and a feed-nip roller system 14.

In operation to produce a bobbin of twisted yarn, a yarn 15 is drawn through the feed-nip roller system 14, through the pigtail ring 17, through the traveller l3 and by the rotation of the spindle 9 on to the bobbin 10 which is carried on the spindle 9. The movement of the yarn 15 through the traveller 13 causes the traveller 13 to circumnavigate the spindle 19 by sliding on the ring 12 and thereby inserts twist into the yarn 15. The ring 12 caused to move up and down with respect to the spindle and the traverse motion is controlled by the method described in FIG. 1 except that the position of the lower switch is controlled by the cam.

In FIG. 3 a hollow spindle 9 carrying a bobbin 10 provided with a cone-shaped flange 16 is mounted on a bearing 11. Positioned above the center of the spindle is a pigtail guide ring 17 and a take-up roller system 18 and positioned below the hollow spindle 9 is a feed-nip roller system 14.

In operation untwisted yarn 19 is fed up the hollow spindle 9. The initially twisted yarn on the bobbin 10 is drawn off the bobbin l0 and is caused to become untwisted by the rotation of the spindle 9 and doubled with the untwisted yarn at the pigtail ring 17. The resultant cord 20 is then taken up on the take-up roller system 18.

To form a cord by inserting twist into a first portion of yarn and then doubling the twisted yarn with a second portion of yarn, the apparatus described in FIGS. 1 and 3 may be employed. Firstly using the apparatus shown in FIG. 1, yarn 15 free from twist is twisted and wound on to the bobbin 10. When the bobbin 10 is filled with twisted yarn and the ring 12 has reached the bottom of its traverse cycle the traversing mechanism of the ring 12 is de-clutched and the traveller 13 is disconnected from the ring 12. In order to disconnect the traveller 13 from the ring 12 the ring may be a split-ring of the type illustrated in FIG. 4. At the same time as the traveller 13 is being disconnected from the ring 12 the twisted portion of yarn 15 is hooked up (mechanism not shown) and passed through the guide ring 17 (FIG. 3) to form the thread line illustrated in FIG. 3. Thus the portion of yarn, which is being continually supplied from the feed-nip roller system 14, is first of all twisted and then the thus twisted portion of yarn is doubled with a second portion of yarn 19 free from twist to form the cord 20.

The invention is illustrated by the following Examples:

EXAMPLE I A nylon yarn of 840 denier with a nominal twist of 0.3 2" t.p.i. was used to make a 2/840 denier tire cord with a nominal twist of 12S'/12.3 2" using the apparatus illustrated in FIGS. 1 and 3.

Firstly, yarn of 0.3 Z t.p.i. after passing through the feednip was taken through the hollow spindle and ring twisted l 2.3 2" t.p.i. in the anti-clockwise direction at 6,000 r.p.m. thus inserting 2" twist into the yarn. The ring and traveller were then disconnected.

The yarn which had been pre-twisted by the method above was ballooned off by rotating the bobbin by 10,000 r.p.m. again in the anti-clockwise direction, and was passed up to the pigtail guide ring. A second yarn having only 0.3 2" t.p.i. was fed up from the feed-nip roller system through the hollow spindle. This substantially untwisted yarn meets the initially twisted yarn at the guide eye which forms the twist point. By suitable adjustment of the relative speeds of feed-nip and takeup nip roller systems a cord with the following tensile proper- EXAMPLE II A polyester yarn of 1,000 denier with a twist of 0.7 S t.p.i. was used to make a 2/1 ,000 denier tire cord with nominal twist of 12 S/l 1.3 Z." The cord was made in two stages as illustrated in FIGS. 2 and 3. Firstly, the 1,000 denier yarn of 0.7 S t.p.i. was down-twisted on a conventional ring twisting frame but with a bobbin placed upsidedown as in FIG. 2 and the spindle turning at 6,000 r.p.m. in the clockwise direction, thus inserting 2" twist in the yarn. The bobbin of twisted yarn was then mounted right side up on the hollow spindle and doubled with a yarn having only 0.7 S" t.p.i. to form a cord in the same was as described in Example I and illustrated in FIG. 3, the hollow spindle rotating at 10,000 rpm in an anticlockwise direction gave a cord having the following tensile properties:

Having now described our invention, what I claim is:

l. A method for the manufacture of cord which comprises continuously passing a continuous filament yarn substantially free from twist upwards through a rotating hollow spindle, inserting twist into a first portion of the yarn, and winding the twisted yarn on to the spindle, discontinuing said twisting and subsequently drawing the first portion of the yarn from the spindle and through a guide means together with a second portion of yarn which is free from twist but still passing through said spindle, while rotating the spindle at a speed commensurate with the number of twists thus causing the first portion to become doubled with the second portion of yarn to form a cord in which the two portions of yarn are substantially free form twist.

2. A method according to claim 1 in which the speed of rotation of the hollow spindle is greater than 5,000 r.p.m.

3. A method according to claim 1 in which the speed of rotation of the hollow spindle is up to 10,500 r.p.m.

4. A method according to claim 1 in which the yarns have filaments formed from tape made by drawing slit film.

5. A method according to claim I in which at least one of the yarns comprises a thermoplastic filament.

6. A method according to claim 5 in which the thermoplastic filament is nylon.

7. A method according to claim 5 in which the thermoplastic filament is poly( ethylene terephthalate).

8. A method according to claim 1 which includes the step of heat-setting the yarns or portions of yarns after they have become doubled together.

9. A method according to claim 8 in which the step of heatsetting the yarns or portion of yarns is carried out by passing the cord through a heated fluidized bed.

10. A method according to claim 3 in which the bobbin is provided with a top flange in the shape of an inverted cone.

11. A method according to claim 1 in which the yarn initially substantially free from twist is supplied to a hollow spindle at a constant rate bearing a constant ratio to the rate at which the cord is drawn off.

12. A method according to claim 1 in which the first portion of yarn is carried on a bobbin on the hollow spindle.

13. A method according to claim 1 in which both the second portion of yarn and the first portion of yarn are multifilament arns. y 14. A method according to claim 1 in which both the first portion of yarn and the second portion of yarn are monofilament yarns. 

1. A method for the manufacture of cord which comprises continuously passing a continuous filament yarn substantially free from twist upwards through a rotating hollow spindle, inserting twist into a first portion of the yarn, and winding the twisted yarn on to the spindle, discontinuing said twisting and subsequently drawing the first portion of the yarn from the spindle and through a guide means together with a second portion of yarn which is free from twist but still passing through said spindle, while rotating the spindle at a speed commensurate with the number of twists thus causing the first portion to become doubled with the second portion of yarn to form a cord in which the two portions of yarn are substantially free form twist.
 2. A metHod according to claim 1 in which the speed of rotation of the hollow spindle is greater than 5,000 r.p.m.
 3. A method according to claim 1 in which the speed of rotation of the hollow spindle is up to 10,500 r.p.m.
 4. A method according to claim 1 in which the yarns have filaments formed from tape made by drawing slit film.
 5. A method according to claim 1 in which at least one of the yarns comprises a thermoplastic filament.
 6. A method according to claim 5 in which the thermoplastic filament is nylon.
 7. A method according to claim 5 in which the thermoplastic filament is poly(ethylene terephthalate).
 8. A method according to claim 1 which includes the step of heat-setting the yarns or portions of yarns after they have become doubled together.
 9. A method according to claim 8 in which the step of heat-setting the yarns or portion of yarns is carried out by passing the cord through a heated fluidized bed.
 10. A method according to claim 3 in which the bobbin is provided with a top flange in the shape of an inverted cone.
 11. A method according to claim 1 in which the yarn initially substantially free from twist is supplied to a hollow spindle at a constant rate bearing a constant ratio to the rate at which the cord is drawn off.
 12. A method according to claim 1 in which the first portion of yarn is carried on a bobbin on the hollow spindle.
 13. A method according to claim 1 in which both the second portion of yarn and the first portion of yarn are multifilament yarns.
 14. A method according to claim 1 in which both the first portion of yarn and the second portion of yarn are monofilament yarns. 